Chief Superintendent Mark Jones called the death of a friend and colleague, along with her two sons, tragic.

He said Det Con Bickley had joined the north Wales force in August 1994, and had served at Bangor, Holyhead and Amlwch - most recently working with the public protection unit "a role she pursued with passion".

Det Con Bickley's husband, John, was being offered support, he added.

He is understood to have been at work and arrived home at about the same time as the emergency services in the early hours of the morning.

Chief Supt Jones added: "She will be sorely missed by friends, colleagues and the local community."

The incident happened near the Anglesey coast

The joint investigation between police officers and the fire service personnel, supported by the forensic science service, is still ongoing at the scene of the fatal house fire.

Emergency crews were called to a bungalow at Tyn y Gongl near the island's coastal resort of Benllech.

North Wales Fire and Rescue could not begin a search until the building was made safe.

The fire gutted the bungalow roof, which then collapsed into the building.

'Shocked and sad'

A fire service spokesperson added: "Crews arrived to find the property well alight. Two sets of breathing apparatus, two hose reel jets and a main jet were used to extinguish the fire.

"The cause of the fire is not yet known and is being investigated jointly by North Wales Fire and Rescue Service and North Wales Police.

Ann Hughes, head teacher at Ysgol Goronwy Owen, Benllech, where the boys went, said: "Very sad news reached us this morning about a fire that has tragically taken the lives of two of our pupils.

"As you can imagine, it is a great shock and loss to the school and the community. Our thoughts are of two very dear and likeable young boys, who have been taken from us in such tragic circumstances.

"As a school we are trying cope as best we can with such a tragedy and are keeping the school day as normal as possible for the pupils. Our deepest sympathy goes out to the family."

Rev Elizabeth Pearce, rector of Llanfair Mathafarn-Eithaf, said: "On behalf of the church and community here in Benllech I should like to say how shocked and sad we are that this tragedy has happened.

"Our thoughts and prayers go out to family and friends - and of course to the emergency services also."